The present invention relates broadly to filter apparatus utilized during the processing of various ores, and, in particular to an improved filter sector for use in a rotary disc filter structure to remove water from an aqueous suspension of ore.
During the processing of ore for the purpose of extracting minerals, numerous grinding, cleaning, and separation processes are conducted. The end product of these processes is frequently a mineral ore concentrate in an aqueous suspension or slurry. The aqueous suspension or slurry must be subjected to successive dewatering or filtering processes to obtain a dry ore concentrate for pelleting or other purification processes. One such filtration process utilizes a rotary disc filter structure which includes a plurality of wedge-shaped filter sectors each of which is covered by a filter bag. The filter sectors are rotated into and out of the slurry or aqueous suspension. Alternately vacuum or pressurized air is applied to draw water through the filter bag accumulating cakes ore concentrate thereon and to provide pressurized air to expand the size of the filter bag causing the ore concentrate to drop off into collection bins.
Since fine particles and also drawn through the filter bag, the filter sector is subjected to abrasion and wear and severe flex stressing due to the cyclic application of vacuum and compressed air. The prior art includes a number of filter sectors which are constructed of heavy metallic materials which are particularly difficult to handle during the relatively frequent changes of the filter bag. The prior art also includes a number of filter sector structures constructed of lighter weight materials but which do not have the ability to withstand the flex stressing as effectively as the metal filter sectors.
The present invention overcomes these disadvantages of the prior art apparatus in that it is an improved filter sector molded of a lightweight elastomeric material having integral, preferably steel, reinforcing ribs that provide the structural stability and rigidity of the filter sector. The present invention also includes substantially abrasion-resistant wear plates disposed at heavy wear positions to increase the time between replacement of parts. The filter sector of the present invention achieves a substantially increased drying efficiency by supporting the filter bag such that the exposure of the bag to drying air is maximized and the channelling of filtered water from the filter sector to the discharge is optimized.